I did some reading on this. Nagle was originally trying to stem the flood of 'tinygrams' sent during lightweight network sessions such as telnet (where single bytes (keystrokes) were being given their own packet, and generating lots of overhead). It's my impression that since many of us are using iSCSI to move large files, we aren't likely to see the algorithm affect us in the way previously described. Is this perhaps why the algorithm is enabled by default?
Blake On 10/24/07, Jonathan Edwards <[EMAIL PROTECTED]> wrote: > > > On Oct 24, 2007, at 14:07, Patrick Sullivan wrote: > > > I recently posted about a serious performance issue when running a > > single thread against my Solaris iSCSI Software Initiator connected > > volume. The cause of this performance issue is due to the Nagle > > algorithm being used for the network traffic sent to and from the > > iSCSI target. Simply disabling the Nagle algorithm solved the > > problem. > > > > Easy enough fix, but it raised a question. If having the Nagle > > algorithm enabled could cause this serious a performance > > degradation (300k/sec I get with it enabled, 40MB/sec with it > > disabled), should it be disabled by default? > > > > I guess I would be curious as to the reason it is enabled by > > default. Does the performance advantage on some targets outweigh > > the performance degradation seen when it is enabled for other > > targets? 300k/sec is pretty dreadful performance, and for most > > applications it could be considered unusable. Granted my testing > > was to the raw device, but any application that accesses the raw > > device directly is also affected by this (think Solaris Volume > > Manager, and I wonder how ZFS would fair, I can test if necessary). > > > > How would I go about filing a request to change the default to not > > use the Nagle algorithm? > > File an RFE here: > http://www.opensolaris.org/bug/report.jspa > > pick the latest nevada release > > --- > .je > > _______________________________________________ > storage-discuss mailing list > [email protected] > http://mail.opensolaris.org/mailman/listinfo/storage-discuss >
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